Describe and give an example (real or hypothetical) of each of the following:

RNA interference

Key Concepts

RNA Interference (RNAi)

RNA interference is a biological process in which RNA molecules inhibit gene expression or translation, effectively silencing targeted genes. This mechanism is crucial for regulating gene activity and defending against viral infections. RNAi is mediated by small RNA molecules, such as small interfering RNA (siRNA) and microRNA (miRNA), which bind to complementary mRNA sequences, leading to their degradation or preventing their translation.

Mechanism of Action

The mechanism of RNA interference involves the processing of double-stranded RNA (dsRNA) into small RNA fragments by an enzyme called Dicer. These small RNA molecules then associate with a protein complex known as the RNA-induced silencing complex (RISC). The RISC uses the small RNA as a guide to recognize and bind to complementary mRNA, resulting in either the cleavage of the mRNA or the inhibition of its translation, thereby silencing the gene.

Applications of RNAi

RNA interference has significant applications in research and medicine, particularly in gene silencing and therapeutic interventions. For example, scientists can use RNAi to knock down the expression of specific genes to study their function or to develop treatments for diseases such as cancer and viral infections. Hypothetically, a therapeutic RNAi could be designed to target and silence a gene responsible for tumor growth, potentially halting cancer progression.